Known spawn locations in the underground:
Xolok the Blind has a significant damage aura 40' range around it (does approximately 21,000 hp dmg per second). It does not summon. Every 35 seconds, it selects a random player on its hate list to follow around. From there, it makes a check every 15 seconds: If, at the time of this check, its target is less than 75' range away, it casts "Fateful Entrapment" on that target (roots the player in place - 1 tick). If its target is more than 110' range away, it casts "Fateful Draw" (pulls the player into its aura - 1-tick pull).